This dissertation asks: why, since 1979, have the seven South Asian states decided to come together in the South Asian Association for Regional Cooperation (SAARC)? Why, in other words, did a region marked by unrivalled differences in size, capabilities, and political systems as well as past and present conflict come to associate? A general explanation of regional association is formulated on the basis of answers to two questions: why do states associate; and what is a region? States associate, it is argued, for three "reasons": because others do; out of affinity for other states; and to better protect or advance cherished values, pre-eminently, status, welfare, and security. A region, it is argued, features the following characteristics: cultural affinity; interdependence, especially "ecological" and specifically in respect of water resources (rivers, seas, oceans); a skewed distribution of power such that a region typically consists of a "core" or "predominant" power and a host of secondary powers; inferiority of status where status rests on the reputation for autonomy and independence in international affairs; and the site of the most important conflicts facing its constituents. Thus, if association is emulative, then regional association has been a popular level of association; if association is by affinity, then a region maximizes affinity; if association arises from threats and opportunities to status, welfare and security, then given feelings of status inferiority, ecological interdependence, the skewedness of power and the rifeness of conflict, regions are where threats and opportunities are most salient.In the case of SAARC--notwithstanding the official rhetoric about "developmental" concerns as well as our findings relating to the desire to emulate other regions, the quest for status and recognition of affinity, the existence of interdependencies in river water management and exploitation--the primary motive for association is security: SAARC is seen as (i) a means of mutual "containment" wherein the small states wish to contain India's power and India wishes to contain the small states' links to extra-regional powers and (ii) an arena for intra-regional conflict resolution.